LONDON — Nine years after former KGB agent Alexander Litvinenko drank radioactive tea at a London hotel, an inquiry into his death ended Friday with his widow claiming President Vladimir Putin ordered the killing — and Moscow accusing Britain of politicizing the probe.

Litvinenko, who fled to London in 2000 and became a fierce critic of Putin, died three weeks after drinking tea laced with radioactive polonim-210. On his deathbed, he accused Putin of ordering his assassination — a claim Moscow denies.

His death continues to be an irritant in worsening relations between the two countries. And despite a six-month inquiry that heard from 62 witnesses, putting anyone on trial for the killing remains a remote prospect.

Outside London's Royal Courts of Justice, Marina Litvinenko said the inquiry had revealed that "my husband was killed by agents of the Russian state ... and this could not have happened without the knowledge and consent of Mr. Putin."

Her lawyer, Ben Emmerson, called Putin a "tin-pot dictator" who had ordered the "liquidation" of an enemy.

The Russian Foreign Ministry slammed the public inquiry, saying that "despite its name it is not transparent, either for Russia or for the general public." It said Moscow had been "actively assisting" the British probe until it began to fear it could be used for political ends.

Marina Litvinenko, left, the widow of former Russian intelligence officer Alexander Litvinenko smiles as she gives a statement, outside the Royal Courts of Justice in London, Friday, July 31, 2015. A lawyer for the widow of ex-KGB agent Alexander Litvinenko says Russian authorities have tried to obstruct an inquiry into his death "from beginning to end." (AP Photo/Ashley Chan)

Emmerson said Moscow had attempted "to frustrate and manipulate" the investigation from the start, by refusing to cooperate and raising objections and obstacles.

British police have accused Dmitry Kovtun and Andrei Lugovoi — the two Russians Litvinenko met for tea — of carrying out the killing, sponsored by elements in the Kremlin. Both deny involvement, and Moscow refuses to extradite them.

That stalemate lasted for years, and investigations into the death were further delayed by Britain's reluctance to disclose secret intelligence evidence about Litvinenko and his links to U.K. spy agencies.

Last year the government announced a judge-led public inquiry. The judge, Robert Owen, has seen the secret evidence, though lawyers, press and the public have not.

British detectives and scientists told the inquiry that scientific evidence points to the guilt of Kovtun and Lugovoi, a former agent in the KGB's successor, the FSB. Traces of highly radioactive polonium were found in hotels, restaurants and other sites across London that they visited.

Litvinenko's killing, with its brutality and echoes of Cold War intrigue, soured relations between London and Moscow. They have since deteriorated further, as the West imposes economic sanctions on Russia over the conflict in eastern Ukraine.

Owen is due to report by the end of the year on who killed Litvinenko, and whether the Russian state was involved. A finding of direct involvement by Putin would likely bring calls for more sanctions, and another downturn in U.K.-Russian relations.

Associated Press writer Nataliya Vasilyeva in Moscow contributed.

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